Characterization of High Dose B⁺ Implanted Ti Thin Films

Abstract

Boron ions were implanted in Ti films with a high dose of 7.14×10¹⁷ and 2.30×10¹⁸ ions/cm². Depth profiles of the concentration of boron ions were measured by a second ary ion mass spectroscopy. Even at extremely high dose implantation of boron ions, the mean project range Rp coincided well with theoretical values predicted from LSS theory. At the dose of 2.30×10¹⁸ ions/cm² the maximum boron ion concentration was higher than that of TiB₃, synthesized by a solid reaction. The formation of very fine-grained TiB₂ was confirmed by X-ray diffraction, and the reaction process is discussed. The temperature coefficient of electrical conductivity of B⁺ implanted 170 nm thick films was as low as 0.3 ppm/K in the temperature range from 4.2 to 350 K, so it was regarded as almos t constant. This fact may be correlated with the microstructure of the implanted films consisting of fine-grained TiB₂ crystallites.